/*
 * Copyright (C) 2011 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.math;

import static com.google.common.math.MathBenchmarking.ARRAY_MASK;
import static com.google.common.math.MathBenchmarking.ARRAY_SIZE;
import static com.google.common.math.MathBenchmarking.RANDOM_SOURCE;
import static com.google.common.math.MathBenchmarking.randomDouble;
import static com.google.common.math.MathBenchmarking.randomPositiveDouble;

import com.google.caliper.BeforeExperiment;
import com.google.caliper.Benchmark;

/**
 * Tests for the non-rounding methods of {@code DoubleMath}.
 *
 * @author Louis Wasserman
 */
public class DoubleMathBenchmark
{
    private static final double[] positiveDoubles = new double[ARRAY_SIZE];
    private static final int[] factorials = new int[ARRAY_SIZE];
    private static final double[] doubles = new double[ARRAY_SIZE];

    @BeforeExperiment
    void setUp()
    {
        for (int i = 0; i < ARRAY_SIZE; i++)
        {
            positiveDoubles[i] = randomPositiveDouble();
            doubles[i] = randomDouble(Long.SIZE);
            factorials[i] = RANDOM_SOURCE.nextInt(100);
        }
    }

    @Benchmark
    long log2(int reps)
    {
        long tmp = 0;
        for (int i = 0; i < reps; i++)
        {
            int j = i & ARRAY_MASK;
            tmp += Double.doubleToRawLongBits(DoubleMath.log2(positiveDoubles[j]));
        }
        return tmp;
    }

    @Benchmark
    long factorial(int reps)
    {
        long tmp = 0;
        for (int i = 0; i < reps; i++)
        {
            int j = i & ARRAY_MASK;
            tmp += Double.doubleToRawLongBits(DoubleMath.factorial(factorials[j]));
        }
        return tmp;
    }

    @Benchmark
    int isMathematicalInteger(int reps)
    {
        int tmp = 0;
        for (int i = 0; i < reps; i++)
        {
            int j = i & ARRAY_MASK;
            if (DoubleMath.isMathematicalInteger(doubles[j]))
            {
                tmp++;
            }
        }
        return tmp;
    }

    @Benchmark
    int isPowerOfTwo(int reps)
    {
        int tmp = 0;
        for (int i = 0; i < reps; i++)
        {
            int j = i & ARRAY_MASK;
            if (DoubleMath.isPowerOfTwo(doubles[j]))
            {
                tmp++;
            }
        }
        return tmp;
    }
}
